Search found 4760 matches

by Jirka
Tue Oct 15, 2019 6:34 pm
Forum: Hydrus 1D
Topic: Electric conductivity and solute concentration
Replies: 1
Views: 4

Re: Electric conductivity and solute concentration

I suggest that you read the following two papers, where we discuss these issues. Note that some simulations from these papers are posted on the HYDRUS website. J. Ramos, T. B., J. Šimůnek, M. C. Gonçalves, J. C. Martins, A. Prazeres, N. L. Castanheira, and L. S. Pereira, Field evaluation of a multic...
by Jirka
Mon Oct 14, 2019 3:43 pm
Forum: Hydrus 1D
Topic: Cumulative root water uptake per subregion
Replies: 1
Views: 7

Re: Cumulative root water uptake per subregion

No. HYDRUS does not keep track of that. Such option would need to be newly coded. You could get actual uptake from different subregions for a particular print time if you integrate the sink term in the Nod_inf.out file. J.
by Jirka
Fri Oct 11, 2019 5:10 pm
Forum: Hydrus 1D
Topic: inquiry about water flow parameters
Replies: 2
Views: 14

Re: inquiry about water flow parameters

The parameter α (denoted as h0 in Kosugi [1996]) has units of [L] and should be entered as such in GUI. J.
by Jirka
Wed Oct 02, 2019 4:07 pm
Forum: Hydrus 1D
Topic: Inverse model in HYDRUS - Water Content Profile
Replies: 4
Views: 53

Re: Inverse model in HYDRUS - Water Content Profile

The results look reasonable to me for the conditions that you described. I assume that the saturated water content is about 0.27 (the water content of the bottom node). Further I would assume that precipitation is smaller than Ks, and as a result, the profile will only reach the water content corres...
by Jirka
Wed Oct 02, 2019 12:57 am
Forum: Hydrus 1D
Topic: Inverse model in HYDRUS - Water Content Profile
Replies: 4
Views: 53

Re: Inverse model in HYDRUS - Water Content Profile

I do not think that it is possible to comment on your project without knowing more details, at the minimum the boundary conditions. J.
by Jirka
Tue Oct 01, 2019 3:21 pm
Forum: HYDRUS (2D/3D)
Topic: Change boundary condition form Atm.BC to Head BC
Replies: 3
Views: 35

Re: Change boundary condition form Atm.BC to Head BC

I do not see how it could be done in one run with the existing model. J.
by Jirka
Tue Oct 01, 2019 3:14 pm
Forum: Hydrus 1D
Topic: Root length input
Replies: 1
Views: 26

Re: Root length input

The Beta function describing the root distribution with depth (in the GUI denoted as "Root [1/cm]") is a function that describes the proportional distribution of potential root water uptake (root distribution) over depth. It does not have any actual values, i.e., it is a relative function. The progr...
by Jirka
Mon Sep 30, 2019 7:19 pm
Forum: HYDRUS (2D/3D)
Topic: How to change an air-entry value
Replies: 1
Views: 24

Re: How to change an air-entry value

You need to use the modified van Genuchten model. This model then has additional parameters Qa (<Qr) and Qm (>Qs). Different values of the Qm parameter will give you different values of the air-entry value. The larger the difference between Qm and Qs, the larger the air-entry value. J.
by Jirka
Mon Sep 30, 2019 7:13 pm
Forum: HYDRUS (2D/3D)
Topic: Change boundary condition form Atm.BC to Head BC
Replies: 3
Views: 35

Re: Change boundary condition form Atm.BC to Head BC

I do not see how you could do all this in one run. You will likely have to split the simulation into multiple simulations for different time periods, while importing the final results of one simulation as an initial condition for the second simulations, etc, and changing the type of BCs. J.
by Jirka
Mon Sep 30, 2019 7:07 pm
Forum: Hydrus 1D
Topic: Water flow parameters in HYDRUS
Replies: 1
Views: 29

Re: Water flow parameters in HYDRUS

Yes, it is the same thing. The l parameter is sometimes referred to as the "tortuosity and pore connectivity" parameter. Mualem recommended a value of 0.5, although other people recommended other values (e.g., Schaap et al. in his papers on Rosetta recommended a value of -1).

J.
by Jirka
Mon Sep 30, 2019 7:03 pm
Forum: Hydrus 1D
Topic: Use Fredlund and Xing as hydraulic model
Replies: 1
Views: 22

Re: Use Fredlund and Xing as hydraulic model

PC-Progress could implement this function(s) into the computational module as a paid service. However, please note that having the analytical function for the retention curve is not sufficient to use HYDRUS to simulate water flow. You also need to have definitions of the capacity function (a derivat...
by Jirka
Fri Sep 27, 2019 6:19 pm
Forum: Hydrus 1D
Topic: No result after successful calculation
Replies: 3
Views: 49

Re: No result after successful calculation

HYDRUS does not recognize any upper limit on the pressure head. It has upper and lower limits only for the Atmospheric BC. J.
by Jirka
Fri Sep 27, 2019 2:24 pm
Forum: Hydrus 1D
Topic: No result after successful calculation
Replies: 3
Views: 49

Re: No result after successful calculation

I cannot see how this could happen. Can you post your project? J.
by Jirka
Thu Sep 26, 2019 2:23 pm
Forum: HYDRUS (2D/3D)
Topic: Solute transport and sub-surface irrigation
Replies: 3
Views: 69

Re: Solute transport and sub-surface irrigation

The code will always assigned as default cValue1 to all boundaries. You need to overwrite it with cValue2 and cValue3. Simply pick the Cauchy BC, overwrite the boundary, and you will be required to enter a code (pointer). That should do it. J.
by Jirka
Thu Sep 26, 2019 2:05 pm
Forum: HYDRUS (2D/3D)
Topic: Boundary Conditions
Replies: 5
Views: 79

Re: Boundary Conditions

Is you can choose any of the standard BCs for the bottom of your profile, why don't you extend the profile all the way to the groundwater level and then fix the pressure head there to keep GWT constant or use no flow to allow water to accumulate there? J.